package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import jodd.util.StringUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {

    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private IFollowService followService;

    @Override
    public Result queryHotBlog(Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog -> {
            this.queryBlogUser(blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);

    }

    @Override
    public Result queryBlogById(Long id) {
        //1.查blog
        Blog blog = getById(id);

        if(blog == null)
            return Result.fail("笔记不存在");

        //2.查blog对应用户
        queryBlogUser(blog);

        //3.查询blog是否点赞
        isBlogLiked(blog);

        return Result.ok(blog);
    }

    private void isBlogLiked(Blog blog) {
        UserDTO user = UserHolder.getUser();
        //用户未登录，直接返回，无需查询是否已经点赞
        if(user == null)
            return;
        //1.获取用户判断当前用户是否点赞
        Long userId = UserHolder.getUser().getId();
        String key = "blog:liked:" + blog.getId();
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());
        blog.setIsLike(score != null);
    }

    @Override
    public Result likeBlog(Long id) {
        //1.获取用户判断当前用户是否点赞
        Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet().score(key, userId.toString());

        if(score == null){
            //2.未点赞，则执行点赞
            //2.1.数据库点赞数+1
            boolean isSuccess = update().setSql("liked = liked + 1").eq("id", id).update();

            //2.2.保存用户id至redis集合  zadd key value score
            if(isSuccess){
                stringRedisTemplate.opsForZSet().add(key,userId.toString(),System.currentTimeMillis());
            }

        }else {
            //3.已点赞，则执行取消点赞
            //3.1数据库点赞数-1
            boolean isSuccess = update().setSql("liked = liked - 1").eq("id", id).update();

            //3.2.从redis集合中删除数据
            if(isSuccess){
                stringRedisTemplate.opsForZSet().remove(key,userId.toString());
            }
        }

        return Result.ok();

    }


    /**
     * 查询top5点赞用户
     * @param id
     * @return
     */
    @Override
    public Result queryBlogLikes(Long id) {
        String key = BLOG_LIKED_KEY + id;
        //1.redis查top5
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if(top5 == null || top5.isEmpty())
            return Result.ok(Collections.emptyList());

        //2.解析用户id
        List<Long> ids = top5.stream().map(Long::valueOf).collect(Collectors.toList());
        String idStr = StrUtil.join(",", ids);

        //3.根据id在数据库查用户 WHERE id IN (5,1) ORDER BY FIELD(id,5,1)
        List<UserDTO> userDTOS = userService.query()
                .in("id",ids).last("ORDER BY FIELD(id," + idStr + ")").list()
                .stream()
                .map(user -> BeanUtil.copyProperties(user, UserDTO.class))
                .collect(Collectors.toList());


        //4.返回用户dto
        return Result.ok(userDTOS);
    }


    /**
     * 保存笔记
     * @param blog
     * @return
     */
    @Override
    public Result saveBlog(Blog blog) {
        //1.获取登录用户并保存
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());

        boolean isSuccess = save(blog);
        if(isSuccess){
            //2.查询笔记作者的所有粉丝
            List<Follow> follows = followService.query().eq("follow_user_id", user.getId()).list();

            //3.推送笔记给所有粉丝
            for (Follow follow : follows) {
                Long userId = follow.getUserId();
                String key = FEED_KEY + userId;

                //4.推送至redis收件箱集合
                stringRedisTemplate.opsForZSet().add(key,blog.getId().toString(),System.currentTimeMillis());
            }

        } else {
            return Result.fail("新增笔记失败");
        }

        return Result.ok(blog.getId());
    }

    /**
     * 分页查询
     * @param max
     * @param offset
     * @return
     */
    @Override
    public Result queryBlogOfFollow(Long max, Integer offset) {
        //1.获取当前用户
        Long userId = UserHolder.getUser().getId();
        String key = FEED_KEY + userId;

        //2.查询收件箱
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet()
                .reverseRangeByScoreWithScores(key, 0, max, offset, 2);

        if(typedTuples == null || typedTuples.isEmpty())
            return Result.ok();

        //3.解析数据:blogId,时间戳/score,偏移量/offset
        List<Long> ids = new ArrayList<>(typedTuples.size());
        long minTime = 0;
        int os = 1;
        for (ZSetOperations.TypedTuple<String> typedTuple : typedTuples) {
            //帖子id
            String idStr = typedTuple.getValue();
            ids.add(Long.valueOf(idStr));
            //offset判断,最小时间重置
            long time = typedTuple.getScore().longValue();
            if(minTime == time){
                os++;
            }else {
                minTime = time;
            }
        }

        //4.查询blog
        String idStr = StrUtil.join(",", ids);
        List<Blog> blogs = query().in("id",ids).last("ORDER BY FIELD(id," + idStr + ")").list();

        for (Blog blog : blogs) {
            //4.1 查blog对应用户
            queryBlogUser(blog);

            //4.2 查询blog是否点赞
            isBlogLiked(blog);
        }

        //5.封装并返回
        ScrollResult scrollResult = new ScrollResult();
        scrollResult.setList(blogs);
        scrollResult.setOffset(os);
        scrollResult.setMinTime(minTime);

        return Result.ok(scrollResult);
    }

    private void queryBlogUser(Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }
}
